18 Mr. W. C. Williamson on the Recent 



cies, but I found many orbicular specimens of the true E. mar- 

 ginata in which the margin was obviously somewhat thickened 

 and rounded, and others which, as already mentioned, showed the 

 horseshoe-like white portion within the margin, nearly surround- 

 ing the transparent centi'c, so that I have no doubt of this being 

 merely a variety of the same. It is often mistaken by collectors 

 for a form of E. gluhosa, to which it sometimes approximates very 

 closely, but from which it may be distinguished by its compressed 

 form. 



I have seen one specimen which was trilocular, having three 

 transparent margins instead of two. 



Long. Diam. 



1 _i_ 



"5^ ' • ' • I'S'o 



1 1 



irU • . • . T77 



T(J(T • • • • T^U 



Swansea, Rossilly, Manorbeer, Portsmouth, Sandwich, Ky- 

 leakin, Mr. Jeffreys. Scarborough, Lamlash Bay, Mr. Bean. Bos- 

 ton ; March. 



3. Entosolenia lineata, nob. PI. II. fig. 18. 



Cell ovate, broadest towards the base, more or less truncated 

 at the upper extremity, which is sometimes furnished with a very 

 small projecting neck, of variable length, in which is the oral ? 

 orifice ; once only I have found it equal to the entire length of 

 the cell. The base, which is rounded, has generally appended to 

 it a small mucro, which is sometimes affixed obliquely, and oc- 

 casionally wholly wanting. Texture translucent, of a pale dull 

 bluish white ; the surface covered with exceedingly numerous 

 longitudinal lines, so fine as to be visible only under a good mi- 

 croscope. Internal tube straight, patulous, reaching nearly to 

 the base of the cell. 



The dull leaden hue of this species appears to be a constant 

 characteristic ; I have usually been able to identify it at a glance 

 from this feature alone. 



It is possible that the Vermiculum urna of Montagu may have 

 been a short stumpy specimen of this form. Montagu only 

 saw a drawing of it. 



Long. Diam. 



1 1 



TTT • • • • aTT 



_i _1_ 



ISTT • • • • 200 



Sandwich, Mr. Jeffreys. Boston ; March : very rare. 



4. E. squamosa. PI. II. fig. 19. 



Vermiculum squamosum, Mont. p. 526. tab. 14. fig. 2. 

 Serpula squamosa, Turt. p. 158. 

 Lagenula squamosa, Flem. p. 235. 

 Lagenula reticulata, MacGillivray, p. 28. 



